EEPORT ON THE DEEP-SEA DEPOSITS. 
329 
here employed, or it takes place only imperfectly, and this is especially the case where 
the bands are rich in alloys of nickel and cobalt. In some of the spherules we ourselves 
detected traces of cobalt, though the experiments were always more or less doubtful owing 
to the small amount of material at our command, and it must be remarked that the 
manganiferous nodules from which the spherules were frequently extracted, or with which 
they were closely associated in the sediments, in nearly all cases contained cobalt and 
nickel, as may be seen by consulting the analyses in Appendix III. 
Fig. 2 represents a magnetic fragment from the same station (S-tation 276), which 
presents certain peculiarities, and dijffers from those hitherto noticed.. It& form is irregular, 
or only partially rounded its mineral nature is also different, as it has no metallic 
nucleus. With reflected light it appears bluish-black, and the surface is less brilliant 
than that of the spherules with metallic centres. The interior of this fragment presents 
a crystalline structure shown by lines of cleavage and by rather regular fractures with 
acute angles ; the direction of the fractures, however, is not constant, but varies at 
different points. The fractures cannot be said to have the same character as the 
cleavages observed in certain meteoric irons. On, the whole, it is very questionable if 
this magnetic fragment be of cosmic origin, and it is merely represented here as a doubtful 
specimen. 
Fig. 12 represents the appearance of the magnetic particles extracted by the magnet 
from a Ked Clay in the Central Pacific, Station 274, 2750 fathoms, after being broken 
down in an agate mortar and treated with an acid solution of sulphate of copper. 
It is to be observed that a certain number of the particles have been covered by copper, 
and are believed to be the flattened metallic nuclei of the black spherules which were 
observed in the sample before pounding in the mortar. The black and opaque fragments 
are pieces of the outer coatings of the black spherules, together with irregular fragments 
of magnetite and titanic iron, derived from the volcanic materials present in the deposit. 
While it may be urged that some of these particles of iron have been derived from 
fragments of eruptive rocks, there seems to be little doubt that those of a circular form 
must have been derived from the black magnetic spherules, and hence are probably of 
cosmic origin. Support is lent to this view from the circumstance that magnetic particles 
from a volcanic tufa from the sea-bottom, in which no spherules are observed, rarely 
contain any of these metallic particles, while they are generally more or less abundant in 
the magnetic particles from a Eed Clay in which the black spherules are observed under 
the microscope. 
Finally, it may be pointed out, with reference to these black magnetic spherules, that 
some of them, and especially the smaller specimens, do not contain any metallic nuclei 
whatever, being formed throughout of a material similar to the black coating surrounding 
the metallie centres. Gustav Rose pointed out long ago that at the periphery of meteor- 
ites rich in iron there was a coating of magnetic oxide similar to that present in these 
(deep-sea DEPOSITS CHALL. EXP. — 1891.) 42 
